Compaq SW3322, SW3324, SW3323 Frame Buffering and Frame Latency, Software Download, 10Overview

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-10Overview

Frame Buffering and Frame Latency

The switch is a store-and-forward switching device. Each frame is copied into switch memory before being forwarded to another port. This method ensures that all forwarded frames conform to a standard Ethernet frame size and have a correct cyclic redundancy check (CRC) for data integrity. This switching method prevents bad frames from traversing the network and using up valuable network bandwidth, as with cut-through switching technology.

To minimize the possibility of dropping frames on congested ports, the switch provides 4 MB of dynamically allocated frame buffering per 8 10/100 ports and 8 MB per gigabit port. This buffer space is used to queue packets for transmission on congested networks. This is an additional advantage over cut- through switching technology, which drops packets immediately when experiencing collisions.

Software Download

The switch supports the industry-standard Trivial File Transfer Protocol (TFTP) for downloading software to the switch. All switch software is stored in a 1 MB sectored Flash ROM. The download feature allows you to easily install software upgrades to the unit. Compaq Networking Management Software includes a TFTP server and a configuration application to allow for the software downloads. Software can alternatively be downloaded via the serial console port using the XMODEM protocol.

A TFTP or XMODEM software download is invoked via the Download Software Menu using the console menus. A TFTP download can also be invoked via SNMP.

Non-volatile Parameter Storage

Important operating parameters such as IP addresses, Spanning Tree configuration, and management security parameters, are stored in non-volatile Flash memory. These values are retained when the switch experiences power interruptions or is powered down for normal maintenance.